Photo-renewable conductivity and pH electroanalytical sensors for on-line monitoring of drinking water quality

This presentation is embedded in the framework of the DrinkAble (DRINKing wAter resilient management comBining process anaLyses, CFD and innovative sEnsor monitoring) Project (funded by Fondazione Cariplo) [1], whose aim is the construction of the so called “Smart Pipe Node”: a compact flange hosting several miniaturized sensors for quantitative, continuous and distributed monitoring of the parameters assessing water quality, risks for health and the efficacy of disinfection. These nodes, are supposed to be installed both in treatment plants (for instance for the optimization of disinfection processes), as well as across the whole distribution network. In this context, one of the major problems encountered by the on-line sensors is the fouling and passivation of the sensing surface, preventing their use for prolonged times without the need of maintenance and substitution. Here, we presented the optimization of low-cost renewable electroanalytical sensors for the determination of two main parameters in drinking water control: conductivity and pH. The innovative aspect of these devices is their photo-renewable transparent surface made of photocatalytic TiO2 coating [2], which can be activated by UV-LEDs integrated in the system. Both the conductivity and pH measurements were performed before and after a forced fouling process, underlying changes in the response of the sensors and subsequent UV-light recovery, allowing the use of this sensors in remote integrated monitoring systems and flow analysis, where short detection time is crucial. [1] www.drinkable.polimi.it [2] V. Pifferi et al., RSC Adv. 5 (2015) 71210–71214. Acknowledgements The authors acknowledge the Fondazione Cariplo, grant no. 2014-1285 for financial support.